Just a word of caution (my opinion only):
If your MacBook still has a platter-based hard disk drive, you may find yourself very disappointed if you upgrade to either Mavericks or Yosemite.
In my experience, BOTH of these seem to require an SSD (solid-state drive) to offer up a level of "performance" that is acceptable.
Using an HDD with either of them may result in "beachball city", so to speak.
So, if you want to keep the current MBPro -and- go to Yosemite, you almost certainly want to install an SSD, as well.
Having said that, -IF- you upgrade to 10.8.5, you will find a more modern OS that runs very well, even with an HDD...